UNITED STATES—When life gives you lemons, it is likely this time of year. Although, the most popular garden varieties of lemon, like ‘Meyer’ and ‘Eureka’, continue to produce at least a few more fruits sporadically through the year. ‘Lisbon’ lemon that is still used in orchard production, and is the ancestor of the household ‘Eureka’ lemon, produces almost all of its fruit in winter, and blooms shortly afterward.
Ripe citrus in the middle of winter impresses those in climates where winter is too cold for much to happen in the garden. They could not grow a citrus tree if they wanted to. Even here, frost can damage some of the more sensitive citrus varieties, like ‘Mexican’ lime. Unlike the fruits of summer, citrus fruits ripen slowly and are not so perishable, so do not need to be harvested right away.
This means that if it is raining, cold or just too wintery to go outside, citrus fruits can be left on the tree until the weather improves. Most of us prefer to pick them in small batches anyway. Ideally, fruit should get picked as it is consumed. Lemons and limes typically get picked individually as needed, until there are so many that some need to be bagged and shared with friends and neighbors.
Mandarin oranges are the most perishable of the citrus. Because their skins are so loosely attached to the pulp, the pulp can oxidize, lose flavor and eventually get dry and pithy. Incidentally, a ‘tangerine’ is merely a Mandarin orange that was developed in North or South America. A surprisingly sour (unknown) Mandarin orange might really be a ‘Rangpur lime’, which is not a lime at all.
Unlike most fruit that continues to ripen after harvest, or pears that actually delay ripening until after harvest, citrus fruits stop developing flavor once picked. It is best to taste them for confirmation of ripe flavor prior to harvest. Some Mandarin oranges may have slightly greenish blotches on them even when completely ripe. The best ‘Valencia’ oranges can look rather yellowish. Grapefruits might mellow if left in their trees past ripeness, but can also inhibit bloom.
Tet, on February 16, will be the Vietnamese New Year’s Day for the Year of the Dog! Any year associated with the dog must be pretty excellent. Anyway, potted and fruited kumquat trees are very traditional decorations for Tet. Although less popular than orange and lemon trees, they are the most compact of the citrus trees, so are therefore the most adaptable to compact home gardens.
They grow slowly and may never reach first floor eaves. The evergreen leaves are a bit thicker, smaller and darker green than those of Mandarin orange. Stems are mostly thornless. The compact growth is quite symmetrical, so might only occasionally need to be trimmed for a stray stem here and there. Clusters of small white flowers bloom about the time the last of the fruit gets harvested.
Kumquat has the distinction of being the ‘other’ citrus. Although the genus is alternatively known as Citrus, experts know it as Fortunella. Those with round fruit are Fortunella japonica. Those with oval fruit are Fortunella marginata. The abundant fruits are not much bigger than big grapes, and are eaten whole, with the seeds spit out. The tart pulp with the sweet skin is a tangy combination.
Horticulturist Tony Tomeo can be contacted at tonytomeo.wordpress.com.